Printing apparatus, printing position adjustment value setting method and printing method

A printing position adjustment value setting method applicable to a printing apparatus for printing on a printing medium by using a printing head for applying ink on the printing medium, said method setting an adjustment value for adjusting a printing position of the printing head, said method comprising the steps of:

• transporting the printing medium to a printing medium supporting face opposite to the printing head along a transfer path by using a transfer mechanism comprising a first roller pair located on an upstream side and a second roller pair located on a downstream side relative to the printing head in a transfer direction of the printing medium along the transfer path;
• printing a predetermined pattern on the printing medium by using the printing head, after positioning the printing medium on the printing medium supporting face;
• transporting the printing medium to a position opposite to an optical sensor;
• reading the predetermined pattern printed on the printing medium by the optical sensor located in a vicinity of the printing head, after positioning the printing medium to the position opposite to the optical sensor;
• and
• setting the adjustment value for adjusting an applying position of the ink to be applied from the printing head based on a result of the reading by the optical sensor,
• wherein pressure in a nipping portion of the first roller pair is greater than pressure in a nipping portion of the second roller pair,
• wherein a first rib group of a plurality of ribs provided in the transfer path at intervals in a direction intersecting the transfer direction and a second rib group of the plurality of ribs provided in the transfer path at intervals in the direction intersecting the transfer direction are located between the first roller pair and the second roller pair in the transfer direction,
• wherein the first rib group is located on the upstream side and the second rib group is located on the downstream side relative to the printing head in the transfer direction, and
• wherein the optical sensor is located above a location between the first rib group and the second rib group in the transfer direction or a location between the first rib group and the first roller pair in the transfer direction.

A printing method for printing on a printing medium by using a printing head for applying ink on the printing medium, comprising the steps of:

• transporting the printing medium to a printing medium supporting face opposite to the printing head along a transfer path by using a transfer mechanism comprising a first roller pair located on an upstream side and second roller pair located on a downstream side relative to the printing head in a transfer direction of the printing medium along the transfer path;
• printing a predetermined pattern on the printing medium by using the printing head, after positioning the printing medium on the printing medium supporting face;
• transporting the printing medium to a position opposite to an optical sensor;
• reading the predetermined pattern printed on the printing medium by the optical sensor located in a vicinity of the printing head, after positioning the printing medium to the position opposite to the optical sensor;
• setting the adjustment value for adjusting a printing position of the printing head;
• and
• performing the printing after adjusting an applying position of the ink to be applied from the printing head on the basis of the adjustment value set by said setting step,
• wherein pressure in a nipping portion of the first roller pair is greater than pressure in a nipping portion of the second roller pair,
• wherein a first rib group of a plurality of ribs provided in the transfer path at intervals in a direction intersecting the transfer direction and a second rib group of the plurality of ribs provided in the transfer path at intervals in the direction intersecting the transfer direction are located between the first roller pair and the second roller pair in the transfer direction,
• wherein the first rib group is located on the upstream side and the second rib group is located on the downstream side relative to the printing head in the transfer direction, and
• wherein the optical sensor is located above a location between the first rib group and the second rib group in the transfer direction or a location between the first rib group and the first roller pair in the transfer direction.